1. Field of the Invention
The present invention relates to an optical disc accessing apparatus, and more specifically to an optical disc accessing apparatus for use in an optical disc-electric filing system equipped with juke boxes.
2. Description of the Related Art
There is a wide use of an optical disc since it can hold a great deal of data, and the access to the stored data thereon can be performed at high speed. On the other hand, in the field of electric filing systems etc., with the spread of LAN (local area network), there is usually provided a juke box equipped with a plurality of optical discs and an optical disc driver which is capable of automatically selecting and picking up a required optical disc, or turning over to access a required surface of an engaged optical disc.
In such an electric filing system, there is usually provided a juke box-control unit for controlling requests, transmitted from a plurality of connected search terminals, for access to optical discs in which required information such as image data etc. is being stored.
While one of the search terminals is accessing image information stored in a predetermined optical disc, if this juke box-control unit receives an access request from another search terminal, the juke box-control unit, providing a busy signal which indicates that the juke box is engaged, registers the access request. Subsequently, after completion of the access in progress, the access to the data requested next is to be conducted.
In other word, the access requests are processed in the order of registration in the conventional optical disc accessing apparatus.
FIG. 4 shows a flow of the controlling operation in the juke box-control unit. When a request for access to data stored on an optical disc is made (Step 1;Y), if the juke box is busy or being engaged (Step 2;Y), the optical disc accessing apparatus registers the access request in the queue in the requested order (Step 3), and places the order. Then, by every certain period of time, or when the busy state of the juke box is freed (Step 2;N), the media requested to be accessed are searched in the registered order in the queue (Step 4), to complete the processing.
Meanwhile, when an access to required in formation is conducted on the order of the juke box-control unit, an optical disc driver provided for an elevator in the juke box is to move physically or spatially to the position of the optical disc designated. For this reason, in a conventional juke box-control unit in which access controls are conducted in the requested order, in a case where, for example, there are made requests for access from plural search terminals to data a-1 on the optical disc A, data b on the optical disc B, and data a-2 on the optical disc A in this order; it is necessary to move the optical disc driver along the elevator one by one for each access request, thus giving rise to a problem to prolong the response time. Such problems have occurred not only in the case where access is made to different optical discs in the same juke box, but also the case where a plurality of juke boxes are connected to the system.